Electromagnetic ratio computing device



1954 A. A. MARKSON 2,686,635

ELECTROMAGNETIC RATIO COMPUTING DEVICE Filed June 11, 1952 2 Sheets-Sheet l AMPLIFIER AND RECTlFlER.

INVENTOR. ALFRED A. MARnso/v A. A. MARKSON 2,686,635

ELECTROMAGNETIC RATIO COMPUTING DEVICE 2 Sheets-Sheet 2 Aug.. 17, 1954 Filed June 11, 1952 d 33 5 3 27 [B INVENTOR.

F5? BfiLf-REO A. MAR/(60A! 96 d Azlfg S.

Patented Aug. 17, 1954 ELECTROMAGNETIC RATIO COMPUTING DEVIC Alfred A. Markson, Mount Lebanon Township,

Allegheny County, Pa., assignor to Hagan Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Application June 11, 1952, Serial No. 293,011

4 Claims.

This invention relates to devices that are provided with variable quantity input responsive means and an output means so arranged. that the value of the output will be proportional to either the product, the quotient, the square, or the square root of the input quantities.

More specifically, the invention relates to electrical device having several current input windings, an electric output device and means for balancing the output against the input, the device being so arranged and constructed that the value of the output can be made proportional to either the product, the quotient, the square, or the square root of the input.

An object of this invention is to provide an electrical device of such construction that an electric output will balance variable electric inputs, with the value of the output being proportional to either the product, the quotient, the square, or the square root of the electric inputs.

The above and other objects and advantages of the invention will be apparent to those skilled in this art from the following description taken in conjunction with the accompanying drawings in which:

Figure 1 is a more or less diagrammatic View of a device arranged and constructed in accordance with an embodiment of the invention, the device being shown connected for operation in a practical application thereof;

Fig. 2 is a top plan view of a component part of the device; and

Figs. 3, 4 and are views showing modified connections of the coils embodied in the device of Fig. 1.

In the drawings a device I embodying a form of the invention is arranged and constructed to receive a plurality of separate variable current inputs IA and IB and to develop a current output 10. The device is so arranged that the output Io may be caused to be proportional to the product, the quotient, the square or square root of the input current or currents, as will appear infra.

The current inputs IA and Is may be developed by devices 3 and 4 that are responsive to the pressure differentials developed across orifices 5 and 6 in pipes or conduits I and 8, respectively, through which a variable quantity, such as fluids or gases flow, for example.

Device l comprises a beam I0, mounted on a fulcrum II, a plurality of input coils A and B and an output current responsive and balancing device I2. The device also includes a differential transformer I3 having a movable core I4 therein which is operatively connected to beam Ill. The

differential transformer I3 comprises coils I5 and I6 and an intermediate coil [1. Coils I5 and It are connected in series in opposed relation to each other, that is, they are so connected that the direction of the field of one coil is opposite in direction to the field in the other coil. The intermediate coil I1 is disposed to be connected to a source of input voltage. The beam it! is provided with a stop I8 whereby under zero input conditions core I4 is in neutral position and the output voltage thereof will be zero. If the beam turns counter-clockwise on its fulcrum It, the output voltage will increase from zero value towards its maximum output value but because of the stop iii, the core I 4 can not pass through zero. The output voltage of the differential transformer is alternating. This output is delivered to a device I9 in which it is amplified and rectified, and the rectified output is delivered to device I2.

Device I2 comprises a permanent magnet of the pot type. The magnet as illustrated, comprises a cup 20 which is open at the top and having a center core 2!. Device I2 includes a coil 22 which is circular or pancake in form so that it may be received in the annular space between the walls of the cup 20 and the central core 2!. The magnetic core 20, 2|, coil 22 and device I9 may be constructed in accordance with the arrangement shown in Fig. 1 of my co-pending application, Serial No. 184,569, filed September 13, 1950. Since the core is a permanent magnet it follows that the force exerted by coil 22 on the beam It and tending to turn it clockwise about fulcrum I I will be directly proportional to the current input to coil 22. The current input to coil 22 is designated Io being the output current of transformer I3 as amplified and rectified.

Coils A and B may be of the pancake type. Coil A, as shown, is suspended by a rod 25 and knife edge 26 from beam I0, while coil B is stationarily mounted on the framework of the device as indicated at 21. The operating air gap between coils A and B should be as small as possible.

In the arrangement of Fig. 1, the input currents to coils A and B are separate currents and have independent values. If the current input to coil A is designated IA, and the current delivered to coil B is designated 113, then it follows that the output current Io in coil 22 of balancing device !2 may be expressed by the equation:

IO KUA'IB) where K is a constant the value of which is primarily determined by the ratio of the lever arms L1 and L2, see Fig. 1.

In order that the performance of the device i may be adjusted so that the product of currents IA and IE will result in an output current Io that 5 is linearly proportional to the product throughout the entire range of the device, shunt resistors 21, 28 and 29 may be connected across the terminals of the respective coils 22, A and B.

Thus, from the above description of Figure l, it has been'shown that the output current I0 is proportional to the product of the currents IA and IE. The instantaneous values of the respective currents Io, IA and IB may be indicated by ammeters C, D and E.

In Figs. 3 and a are illustrated modified connections of the coils of the device whereby the value of current in coil A and in coil B may be caused to be proportional to the quotient of the output current I0 and the current in either coil A or coil B.

As shown in Fig. 3, coil 22 is connected in series with coil B. Coil A is supplied with an input current IA. With the coils connected as in Fig.

3, beam it will be in balance when the force 25 developed by coil 22 is equal to the force de veloped by coils A and B on the beam. The force produced by coil 22 is proportional to the current I0 and may be expressed by the equation:

The force produced by coils A and B may be expressed by the equation:

at balance,

22 FAB e IE The value may be derived as follows:

When F22=FAB the sum of the moments of these forces about the fulcrum i is zero as shown by the following:

F22L2FABL1:0 .'.F22L2:FABL1 and F22=%FAB 2 .'.F22:KF'AB where Pi: L F22=Io and FAB=IAIB .'.Io=KIA'IB and Io K IJ E) where 1 KXK when IB=I0 then IA=KX.

If an ammeter 3G is placed in the circuit of coils 22 and B, it follows that the value of current indicated by that ammeter will be proportional to the products of the currents in coils A and B. If an ammeter 3! is placed in circuit with coil A, it follows that the value of current indicated by that ammeter will be proportional to the quotient of the output current I0 and the input current 13 to coil B.

In Fig. i the hookup illustrated differs from the hookup of Fig. 3 in that in Fig. 4 coil A is connected in series with coil 22 and coil B receives an independent current input IB. The value of current 113 is proportional to the quotient of current lo and the current IA; that is,

where K is a constant. The equation I0 I B K may be derived by following the same procedure as given supra for deriving the equations IA=KX,

-'. 10:? (I -I3) =K3( A B) where 1 If IAIIB then Io KI; (IB) 2 If IB=IA then IO=K3(IA)2 If an ammeter 33 is placed in circuit with the coils A and B to measure the current input and an ammeter 3t is placed in circuit with coil 22 to measure the current output, it follows that the where where ammeter 33 will indicate values of current that are proportional to the square root of the output current Io in coil 22, and that ammeter 34 will indicate values of current that are proportional to the square of the current in coils A and B, or the square of the values of current indicated by ammeter 33.

From the foregoing description it will be ap parent to those skilled in this art that various modifications and changes may be made in the nents of the invention without illustrated embed departing from either the spirit or the scope thereof. Therefore, what is claimed as new and desired to be secured by Letters Patent is:

1. An electro-magnetic input versus output relation device comprising a beam, a fulcrum therefor, a transformer having a core means for lnn'm g movement of the beam and core between a position corresponding to zero output voltage of the transformer and one maximum output voltage position thereof, whereby, as the beam and core are actuated between said positions, the output voltage of the transformer will vary between zero and one maximum value, means for amplifying and rectifying said output voltage, an electro-magnetic balancing device comprising a permanent magnet core and a coil movable relative to the core, said coil being mechanically connected to said beam at one side or" the fulcrum and electrically connected in circuit with said rectified output, a plurality of magnetically coupled coil windings for receiving variable current inputs, one of said coil windings being mechanically connected to said beam to oppose the force of the coil of said permanent magnet, the input coil winding mechanically connected to said beam being movable relative to the other input coil winding, the force exerted by said input coll windings being in proportion to the product or" currents thereof, and the output curr nt to the coil of said electro-magnetic device being proportional to said product and automatically balancing the force of said input coil windings on said beam.

2. A device according to claim 1 in Which the input coil windings are connected in series whereby the force exerted thereby on the beam is proportional to the square of the current input thereto, and the current output to the coil or" said electro-magnetic device is proportional to the square of said input current, the value of the input current being proportional to the square root of the output current.

3. A device according to claim 1 characterized by the fact that the output coil and one of the input coil windings are connected in series whereby when current flows in the other coil the value thereof at balance will be proportional to the quotient of the output current and the current in the other of said input coils.

4. A device according to claim 1 characterized by the fact that the fields of the input coils are air coupled.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,578,831 Keeler Mar. 30, 1926 2,098,654 Carter Nov. 9, 1937 2,310,955 Hornfeck Feb. 16, 1943 2,439,891 Hornfeck Apr. 20, 1948 

